Study On The Method And Mechanism Of Green High Effcient DE-Crosslinking Of Waste Rubber

Rubber, as an important strategic resource in China, has been in short supply. As a giant environmental problems, China is faced with a huge amount of waste rubber resources to dealing with. Only in 2014, China's waste tires has reached 11.35 million tons. How to effectively recycling waste rubber in a lower energy consumption, environmental protection and regeneration ways has become the key to solve the shortage of rubber resources and the problem of solid waste environmental pollution in our country. In the technical field of reclaiming waste rubber, "desulfurizing" mainly through the interaction of obtaining a variety of regeneration mechanisms, convenient for getting higher sol content. But these processes didn't give enough attention to the selectivity of de-crosslinking during the regeneration, and it is not able to carry out the green and efficient regeneration. From the view of molecular bond energy, elastic potential energy and selective solution, this paper studies on selective de-crosslinking process of vulcanized natural rubber in three ways of shearing, thermal effect and chemical interaction, and explores the feasible method and mechanism of the green high efficient de-crosslinking process of waste rubber.Under the condition of oxygen separation, with the shearing effect of the non-permanent fracture by Rubber processing analyzer (RPA), the selective de-crosslinking of vulcanized natural rubber to a certain extent is realized. Under the temperature of 220?, the shearing effect effectively protects the main-chain of rubber, improves the de-crosslinking content(up to 66.49%), and gets to the regeneration aim of high efficiency and selectivity de-crosslinking with greatly reducing on crosslinking density.Using thermal effect under oxygen-free environment by RPA and Vacuum pressing machine, the de-crosslinking process of vulcanized natural rubber under different temperature conditions is studied. The experimental results show that through oxygen separation process, the thermal effect under the temperature of no more than 230? can be used for de-crosslinking network effectively, but it can't achieve a high degree of de-crosslinking content(up to 59.53%). Under a higher temperature condition (>230?), a higher degree of de-crosslinking content can be obtained by the thermal effect in oxygen-free environment. But the main-chain is seriously destroyed. The temperature of the thermal effect has important reference value for the protection of the rubber main chain during the de-crosslinking process.The de-crosslinking experiments of the vulcanized rubber in the swelling state are carried out by using Dithiothreitol (DTT). Within the temperature of 100? and the condition of fully protecting the rubber main chain, through the effective reduction reaction to generate stable cyclic oxidation structure, the vulcanized rubber are effective de-crosslinking by the toluene solution of DTT. The reclaimed rubber with high degree of de-crosslinking content (99.80%) and high molecular weight (5.47×104) are obtained. The aim of high efficiency and selectivity de-crosslinking is achieved.